Deep-well turbine pump

Deep-well turbine pumps are a type of vertical shaft submersible pump. They are also known as vertical turbine pumps, vertical line shafts pumps and lineshaft turbine pumps. They are borehole pumps, whose pump shaft extends up to ground level, where it is coupled to a dry installed motor (e.g. hollow shaft motor) or gearbox (e.g. hollow shaft gearbox). They are multistage pumps and usually fitted with mixed flow impellers. See Fig. 1 Deep-well turbine pump

Deep-well turbine pumps can be extended in modules (shaft sections). Large installation lengths are produced by means of standard extension sets consisting of an intermediate shaft, an intermediate coupling (e.g. threaded coupling, conical coupling or split muff coupling), a column pipe and a bearing spider.

The suction strainer (also see Valve), foot valve (for installation depths exceeding 10 m), pump and vertical discharge line (riser) are suspended from the motor stool, on which the drive is mounted and which contains the discharge elbow) of the pump. The thrust bearing serves to absorb the axial thrust and support the rotor weight. It is located in the motor stool, hollow shaft motor or hollow shaft gearbox.

The drive shaft transfers the driving torque as well as the axial thrust. It is supported by water-lubricated plain bearings inside the column pipe. If the boreholes or wells are very deep, the drive shaft and intermediate bearings tend to push up the overall cost of the installation (see Economic efficiency), and it becomes more advantageous to install borehole pumps with submersible motors instead.

In the absence of a power grid, deep-well turbine pumps are often driven by combustion engines connected by means of a right-angle gear (e.g. tractors in agricultural applications).